A nomadic city moves from place to place like an enormous tank in this conceptual proposal by architecture graduate Manuel Domínguez.
Entitled Very Large Structure, the futuristic megastructure is designed to wheel itself from one location to another to find better economic and physical conditions. Rather than using up the resources of the places it visits, it would be able to produce its own energy and establish new buildings before moving on.
Total length would be 560 meters. It could be built with today's technology.
The most obvious use I see for such a structure, however, is not on Earth at all. It is on Mercury. If this structure can be made to roll along at about 7 mph (perhaps powered by the abundant solar energy--according to my calculations, you would get nearly 10,000 watts per square meter so close to the sun) you can keep up with the terminator line and stay in perpetual twilight and earthlike temperatures.
Credit: Manuel Dominguez
Basically imagine these with massive solar arrays attached and you have what I think a Mercury colony will look like. Will's timeline has something like this, but on rails instead of caterpillar tracks. I think this version is more badass and self-reliant, better able to adapt if something goes wrong.
And in my future canon, the first colony on Mercury will be called Dominguez City. It'll be established in the 2140s.